Tim Wigmore works on the Morning Briefing email and was called a "little slave" by the Daily Politics Show. He blogs on British politics, and also contributes to ESPNcricinfo. He tweets @timwig.

America is becoming less religious. That's good news for the Democrats

It might not look like it, but US Christianity is shrinking (Photo: Getty)

Americans overwhelmingly think religion is a Good Thing. But they seem to be ignoring their own opinion: religion in the USA is in steady decline.

The number of Americans who describe their religious preference as "no religion" is now 20 per cent, according to a new study. There is "no evidence of a slowdown" in this tendency, which has risen from eight per cent in 1990 and 14 percent in 2000. Ethnic minorities remain generally more religious, but this has become less true as they have become increasingly integrated into American society. The number of Hispanics with no religious affiliation has risen by 9.7 per cent since 1990; the number of African-Americans by 13.7 percent.

This is all bad news for the Republicans. Much of their strategy for winning Hispanic support is based on shared social conservative values – but, as these become less pronounced among Hispanics, Republicans will need to find alternative ways of appealing. And, while churches remain an important source of political mobilisation and fund-raising – one that the Republicans tap far more effectively than the Democrats – the 2012 election suggested that the GOP is over-dependent on social conservatism to win support.

American politics is increasingly defined by a religious faultline. And, as elsewhere, both parties are increasingly populated by echoing voices. While 39.6 percent of political liberals – a rise of 25 percent from 1990 – declare their religious preference to be "no religion", less than 10 percent of political conservatives do so. It's notable that the figure for self-declared political moderates, of 18 percent, is much closer to that of conservatives than liberals – suggesting a danger for the Democrats of ostracising religion too quickly. But the attitudes of America's young reaffirm the direction of travel: 32 percent of 18-to-24 year olds also prefer no religion.

This trend is clear, yet we are some way off being able to declare America as secular as the rest of the West. Only three percent of Americans say that they do not believe in God. And Americans still regard faith as a Good Thing in a way that Europeans do not. A Gallup poll today showed that, even as 77 percent of Americans think that religion is losing its influence on American life, 75 percent think that society would be better off if more Americans were religious.

As in other areas, the long-term trends in American society give the Democrats hope of establishing an era of electoral dominance. But they should be wary that their own secularisation is outpacing America's.